/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		Definitions for the TCP protocol.
 *
 * Version:	@(#)tcp.h	1.0.2	04/28/93
 *
 * Author:	Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 */
#ifndef _LINUX_TCP_H
#define _LINUX_TCP_H

#include <linux/types.h>
#include <asm/byteorder.h>
#include <linux/socket.h>

struct tcphdr {
	__be16 source;
	__be16 dest;
	__be32 seq;
	__be32 ack_seq;
#if defined(__LITTLE_ENDIAN_BITFIELD)
	__u16 res1:4,
	    doff:4, fin:1, syn:1, rst:1, psh:1, ack:1, urg:1, ece:1, cwr:1;
#elif defined(__BIG_ENDIAN_BITFIELD)
	__u16 doff:4,
	    res1:4, cwr:1, ece:1, urg:1, ack:1, psh:1, rst:1, syn:1, fin:1;
#else
#error	"Adjust your <asm/byteorder.h> defines"
#endif
	__be16 window;
	__sum16 check;
	__be16 urg_ptr;
};

/*
 *	The union cast uses a gcc extension to avoid aliasing problems
 *  (union is compatible to any of its members)
 *  This means this part of the code is -fstrict-aliasing safe now.
 */
union tcp_word_hdr {
	struct tcphdr hdr;
	__be32 words[5];
};

#define tcp_flag_word(tp) ( ((union tcp_word_hdr *)(tp))->words [3])

enum {
	TCP_FLAG_CWR = __constant_htonl(0x00800000),
	TCP_FLAG_ECE = __constant_htonl(0x00400000),
	TCP_FLAG_URG = __constant_htonl(0x00200000),
	TCP_FLAG_ACK = __constant_htonl(0x00100000),
	TCP_FLAG_PSH = __constant_htonl(0x00080000),
	TCP_FLAG_RST = __constant_htonl(0x00040000),
	TCP_FLAG_SYN = __constant_htonl(0x00020000),
	TCP_FLAG_FIN = __constant_htonl(0x00010000),
	TCP_RESERVED_BITS = __constant_htonl(0x0F000000),
	TCP_DATA_OFFSET = __constant_htonl(0xF0000000)
};

/* TCP socket options */
#define TCP_NODELAY		1	/* Turn off Nagle's algorithm. */
#define TCP_MAXSEG		2	/* Limit MSS */
#define TCP_CORK		3	/* Never send partially complete segments */
#define TCP_KEEPIDLE		4	/* Start keeplives after this period */
#define TCP_KEEPINTVL		5	/* Interval between keepalives */
#define TCP_KEEPCNT		6	/* Number of keepalives before death */
#define TCP_SYNCNT		7	/* Number of SYN retransmits */
#define TCP_LINGER2		8	/* Life time of orphaned FIN-WAIT-2 state */
#define TCP_DEFER_ACCEPT	9	/* Wake up listener only when data arrive */
#define TCP_WINDOW_CLAMP	10	/* Bound advertised window */
#define TCP_INFO		11	/* Information about this connection. */
#define TCP_QUICKACK		12	/* Block/reenable quick acks */
#define TCP_CONGESTION		13	/* Congestion control algorithm */
#define TCP_MD5SIG		14	/* TCP MD5 Signature (RFC2385) */

#define TCPI_OPT_TIMESTAMPS	1
#define TCPI_OPT_SACK		2
#define TCPI_OPT_WSCALE		4
#define TCPI_OPT_ECN		8

enum tcp_ca_state {
	TCP_CA_Open = 0,
#define TCPF_CA_Open	(1<<TCP_CA_Open)
	TCP_CA_Disorder = 1,
#define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
	TCP_CA_CWR = 2,
#define TCPF_CA_CWR	(1<<TCP_CA_CWR)
	TCP_CA_Recovery = 3,
#define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
	TCP_CA_Loss = 4
#define TCPF_CA_Loss	(1<<TCP_CA_Loss)
};

struct tcp_info {
	__u8 tcpi_state;
	__u8 tcpi_ca_state;
	__u8 tcpi_retransmits;
	__u8 tcpi_probes;
	__u8 tcpi_backoff;
	__u8 tcpi_options;
	__u8 tcpi_snd_wscale:4, tcpi_rcv_wscale:4;

	__u32 tcpi_rto;
	__u32 tcpi_ato;
	__u32 tcpi_snd_mss;
	__u32 tcpi_rcv_mss;

	__u32 tcpi_unacked;
	__u32 tcpi_sacked;
	__u32 tcpi_lost;
	__u32 tcpi_retrans;
	__u32 tcpi_fackets;

	/* Times. */
	__u32 tcpi_last_data_sent;
	__u32 tcpi_last_ack_sent;	/* Not remembered, sorry. */
	__u32 tcpi_last_data_recv;
	__u32 tcpi_last_ack_recv;

	/* Metrics. */
	__u32 tcpi_pmtu;
	__u32 tcpi_rcv_ssthresh;
	__u32 tcpi_rtt;
	__u32 tcpi_rttvar;
	__u32 tcpi_snd_ssthresh;
	__u32 tcpi_snd_cwnd;
	__u32 tcpi_advmss;
	__u32 tcpi_reordering;

	__u32 tcpi_rcv_rtt;
	__u32 tcpi_rcv_space;

	__u32 tcpi_total_retrans;
};

/* for TCP_MD5SIG socket option */
#define TCP_MD5SIG_MAXKEYLEN	80

struct tcp_md5sig {
	struct __kernel_sockaddr_storage tcpm_addr;	/* address associated */
	__u16 __tcpm_pad1;	/* zero */
	__u16 tcpm_keylen;	/* key length */
	__u32 __tcpm_pad2;	/* zero */
	__u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN];	/* key (binary) */
};

#ifdef __KERNEL__

#include <linux/skbuff.h>
#include <linux/dmaengine.h>
#include <net/sock.h>
#include <net/inet_connection_sock.h>
#include <net/inet_timewait_sock.h>

static inline struct tcphdr *tcp_hdr(const struct sk_buff *skb)
{
	return (struct tcphdr *)skb_transport_header(skb);
}

static inline unsigned int tcp_hdrlen(const struct sk_buff *skb)
{
	return tcp_hdr(skb)->doff * 4;
}

static inline unsigned int tcp_optlen(const struct sk_buff *skb)
{
	return (tcp_hdr(skb)->doff - 5) * 4;
}

/* This defines a selective acknowledgement block. */
struct tcp_sack_block_wire {
	__be32 start_seq;
	__be32 end_seq;
};

struct tcp_sack_block {
	u32 start_seq;
	u32 end_seq;
};

struct tcp_options_received {
/*	PAWS/RTTM data	*/
	long ts_recent_stamp;	/* Time we stored ts_recent (for aging) */
	u32 ts_recent;		/* Time stamp to echo next              */
	u32 rcv_tsval;		/* Time stamp value                     */
	u32 rcv_tsecr;		/* Time stamp echo reply                */
	u16 saw_tstamp:1,	/* Saw TIMESTAMP on last packet         */
	 tstamp_ok:1,		/* TIMESTAMP seen on SYN packet         */
	 dsack:1,		/* D-SACK is scheduled                  */
	 wscale_ok:1,		/* Wscale seen on SYN packet            */
	 sack_ok:4,		/* SACK seen on SYN packet              */
	 snd_wscale:4,		/* Window scaling received from sender  */
	 rcv_wscale:4;		/* Window scaling to send to receiver   */
/*	SACKs data	*/
	u8 eff_sacks;		/* Size of SACK array to send with next packet */
	u8 num_sacks;		/* Number of SACK blocks                */
	u16 user_mss;		/* mss requested by user in ioctl */
	u16 mss_clamp;		/* Maximal mss, negotiated at connection setup */
};

/* This is the max number of SACKS that we'll generate and process. It's safe
 * to increse this, although since:
 *   size = TCPOLEN_SACK_BASE_ALIGNED (4) + n * TCPOLEN_SACK_PERBLOCK (8)
 * only four options will fit in a standard TCP header */
#define TCP_NUM_SACKS 4

struct tcp_request_sock {
	struct inet_request_sock req;
#ifdef CONFIG_TCP_MD5SIG
	/* Only used by TCP MD5 Signature so far. */
	struct tcp_request_sock_ops *af_specific;
#endif
	u32 rcv_isn;
	u32 snt_isn;
};

static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
{
	return (struct tcp_request_sock *)req;
}

struct tcp_sock {
	/* inet_connection_sock has to be the first member of tcp_sock */
	struct inet_connection_sock inet_conn;
	u16 tcp_header_len;	/* Bytes of tcp header to send          */
	u16 xmit_size_goal;	/* Goal for segmenting output packets   */

/*
 *	Header prediction flags
 *	0x5?10 << 16 + snd_wnd in net byte order
 */
	__be32 pred_flags;

/*
 *	RFC793 variables by their proper names. This means you can
 *	read the code and the spec side by side (and laugh ...)
 *	See RFC793 and RFC1122. The RFC writes these in capitals.
 */
	u32 rcv_nxt;		/* What we want to receive next         */
	u32 copied_seq;		/* Head of yet unread data              */
	u32 rcv_wup;		/* rcv_nxt on last window update sent   */
	u32 snd_nxt;		/* Next sequence we send                */

	u32 snd_una;		/* First byte we want an ack for        */
	u32 snd_sml;		/* Last byte of the most recently transmitted small packet */
	u32 rcv_tstamp;		/* timestamp of last received ACK (for keepalives) */
	u32 lsndtime;		/* timestamp of last sent data packet (for restart window) */

	/* Data for direct copy to user */
	struct {
		struct sk_buff_head prequeue;
		struct task_struct *task;
		struct iovec *iov;
		int memory;
		int len;
#ifdef CONFIG_NET_DMA
		/* members for async copy */
		struct dma_chan *dma_chan;
		int wakeup;
		struct dma_pinned_list *pinned_list;
		dma_cookie_t dma_cookie;
#endif
	} ucopy;

	u32 snd_wl1;		/* Sequence for window update           */
	u32 snd_wnd;		/* The window we expect to receive      */
	u32 max_window;		/* Maximal window ever seen from peer   */
	u32 mss_cache;		/* Cached effective mss, not including SACKS */

	u32 window_clamp;	/* Maximal window to advertise          */
	u32 rcv_ssthresh;	/* Current window clamp                 */

	u32 frto_highmark;	/* snd_nxt when RTO occurred */
	u16 advmss;		/* Advertised MSS                       */
	u8 frto_counter;	/* Number of new acks after RTO */
	u8 nonagle;		/* Disable Nagle algorithm?             */

/* RTT measurement */
	u32 srtt;		/* smoothed round trip time << 3        */
	u32 mdev;		/* medium deviation                     */
	u32 mdev_max;		/* maximal mdev for the last rtt period */
	u32 rttvar;		/* smoothed mdev_max                    */
	u32 rtt_seq;		/* sequence number to update rttvar     */

	u32 packets_out;	/* Packets which are "in flight"        */
	u32 retrans_out;	/* Retransmitted packets out            */

	u16 urg_data;		/* Saved octet of OOB data and control flags */
	u8 ecn_flags;		/* ECN status bits.                     */
	u8 reordering;		/* Packet reordering metric.            */
	u32 snd_up;		/* Urgent pointer               */

	u8 keepalive_probes;	/* num of allowed keep alive probes   */
/*
 *      Options received (usually on last packet, some only on SYN packets).
 */
	struct tcp_options_received rx_opt;

/*
 *	Slow start and congestion control (see also Nagle, and Karn & Partridge)
 */
	u32 snd_ssthresh;	/* Slow start size threshold            */
	u32 snd_cwnd;		/* Sending congestion window            */
	u32 snd_cwnd_cnt;	/* Linear increase counter              */
	u32 snd_cwnd_clamp;	/* Do not allow snd_cwnd to grow above this */
	u32 snd_cwnd_used;
	u32 snd_cwnd_stamp;

	u32 rcv_wnd;		/* Current receiver window              */
	u32 write_seq;		/* Tail(+1) of data held in tcp send buffer */
	u32 pushed_seq;		/* Last pushed seq, required to talk to windows */
	u32 lost_out;		/* Lost packets                 */
	u32 sacked_out;		/* SACK'd packets                       */
	u32 fackets_out;	/* FACK'd packets                       */
	u32 tso_deferred;
	u32 bytes_acked;	/* Appropriate Byte Counting - RFC3465 */

	/* from STCP, retrans queue hinting */
	struct sk_buff *lost_skb_hint;
	struct sk_buff *scoreboard_skb_hint;
	struct sk_buff *retransmit_skb_hint;

	struct sk_buff_head out_of_order_queue;	/* Out of order segments go here */

	/* SACKs data, these 2 need to be together (see tcp_build_and_update_options) */
	struct tcp_sack_block duplicate_sack[1];	/* D-SACK block */
	struct tcp_sack_block selective_acks[4];	/* The SACKS themselves */

	struct tcp_sack_block recv_sack_cache[4];

	struct sk_buff *highest_sack;	/* highest skb with SACK received
					 * (validity guaranteed only if
					 * sacked_out > 0)
					 */

	int lost_cnt_hint;
	u32 retransmit_high;	/* L-bits may be on up to this seqno */

	u32 lost_retrans_low;	/* Sent seq after any rxmit (lowest) */

	u32 prior_ssthresh;	/* ssthresh saved at recovery start     */
	u32 high_seq;		/* snd_nxt at onset of congestion       */

	u32 retrans_stamp;	/* Timestamp of the last retransmit,
				 * also used in SYN-SENT to remember stamp of
				 * the first SYN. */
	u32 undo_marker;	/* tracking retrans started here. */
	int undo_retrans;	/* number of undoable retransmissions. */
	u32 total_retrans;	/* Total retransmits for entire connection */

	u32 urg_seq;		/* Seq of received urgent pointer */
	unsigned int keepalive_time;	/* time before keep alive takes place */
	unsigned int keepalive_intvl;	/* time interval between keep alive probes */

	unsigned long last_synq_overflow;

/* Receiver side RTT estimation */
	struct {
		u32 rtt;
		u32 seq;
		u32 time;
	} rcv_rtt_est;

/* Receiver queue space */
	struct {
		int space;
		u32 seq;
		u32 time;
	} rcvq_space;

/* TCP-specific MTU probe information. */
	struct {
		u32 probe_seq_start;
		u32 probe_seq_end;
	} mtu_probe;

#ifdef CONFIG_TCP_MD5SIG
/* TCP AF-Specific parts; only used by MD5 Signature support so far */
	struct tcp_sock_af_ops *af_specific;

/* TCP MD5 Signagure Option information */
	struct tcp_md5sig_info *md5sig_info;
#endif

	int linger2;
};

static inline struct tcp_sock *tcp_sk(const struct sock *sk)
{
	return (struct tcp_sock *)sk;
}

struct tcp_timewait_sock {
	struct inet_timewait_sock tw_sk;
	u32 tw_rcv_nxt;
	u32 tw_snd_nxt;
	u32 tw_rcv_wnd;
	u32 tw_ts_recent;
	long tw_ts_recent_stamp;
#ifdef CONFIG_TCP_MD5SIG
	u16 tw_md5_keylen;
	u8 tw_md5_key[TCP_MD5SIG_MAXKEYLEN];
#endif
};

static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
{
	return (struct tcp_timewait_sock *)sk;
}

#endif

#endif /* _LINUX_TCP_H */
